Biology 124 (Cusic) Exam IV Notes

Biology 124 (Cusic) Exam IV Notes - • Communication...

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Communication between cells o Communication b/w yeast cells – different mating type send out factor and response and fuse o Gap junctions between animal cells o Plasmodesmata between plant cells o Cells recognition through binding o Local distance Paracrine signaling – send out a signal to target cells (cytokines in immune system) Synaptic signaling – nerve cells send out neurotransmitter across the synapse o Long distance Hormonal signaling – the endocrine system (gland) make the signal (hormone) and send them through the blood to affect certain things o Signal transduction path way – signal binds to the receptor – affect relay molecules to activate cellular response o 3 types of receptors G-Protein-linked receptors – signal binding (Ligand) binds to the receptor in the cell membrane GDP – inactive Signal molecules bind to the receptor and activate the G- protein by switching GTP with GDP G-protein then activate the local inactive enzyme GTPase – active enzyme break down GTP in the G-protein back to GDP (inactive form) Potulism disease – break down the GDP disease Tyrosine kinases Transfer a phosphate Two monomers become dimmers (active) When the signals bind to each monomer – bind the two monomers together – 6 ATP turn into 6 ADP – activate inactive proteins in the cells Important in cells stepwise process Phosphorylation cascade Stepwise process of a relay (transduction) The final results consisted of the product from all the relays Amply the signals from small amount of hormones Membrane receptors: ion channel receptors Gated proteins Open the gate by specific ligand signal Trigger the concentration gradient of ions Second messenger system
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Cyclic AMP Adenylyl cyclase turn ATP into Cyclic AMP as second messenger from the binding of G protein after the first messenger (hormone) binded to the G-protein linked receptor Second messenger is the one that does all the work Phosphodiesterase then turn Cyclic AMP into AMP to terminate the response Maintenance of Calcium ions Calcium concentration outside the cells is higher than inside the cells Ca 2+ pumps are in the membrane of the cells and on the storage of calcium inside the cells Inositol triphosphate – signals come in and bind the G- protein receptor – G protein activates phospholipase C – phospholipase C then work on PIP 2 to produce DAG and IP 3 (second messenger) [produce/release hormones as an example] – IP 3 binds to the gated calcium channel to open it and allow calcium to move in and out – released calcium activate various proteins Nuclear responses: activation of growth factor Growth factor turns on inactive transcription factor in the cells to trigger the genes response through phosphorylation cascade Steroid hormone Bind to the receptors inside the cell not in the cell membrane After the hormone receptor complex is turned on, the whole
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This note was uploaded on 04/07/2008 for the course BY 124 taught by Professor Cusic during the Spring '08 term at University of Alabama at Birmingham.

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Biology 124 (Cusic) Exam IV Notes - • Communication...

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